1. Field of the Invention
The present invention relates to an exhaust gas combustion device and a power generator including the device. In particular, the present invention relates to an exhaust gas combustion device that combusts exhaust gas discharged from a diesel engine and also to a power generator including the device.
2. Description of the Related Art
A general power generator obtains power by driving a power generating unit by an engine. When a diesel engine is employed as the engine, particulate matter (hereinbelow, abbreviated as PM) contained in exhaust gas from the engine needs to be removed.
One method for removing PM from exhaust gas is to dispose a diesel particulate filter (hereinbelow, abbreviated as DPF) made of a porous material in an exhaust pipe through which exhaust gas discharged from a diesel engine passes. By this method, most of the PM contained in the exhaust gas is collected by the DPF. Therefore, the exhaust gas discharged to the outside is highly purified.
However, after continuous operation of the diesel engine over a long period of time, the DPF with the PM adhering thereto comes to block the flow of exhaust gas. This, as a result, causes a problem of lowering the output of the diesel engine. Thus, regeneration operation is generally performed to remove the PM adhering to the DPF.
One example of the regeneration operation is thermal regeneration which regenerates a filter by combusting PM by heating. In the thermal regeneration, after PM contained in exhaust gas is collected by a DPF, an electric heater provided to the DPF is electrified to heat and combust the PM, whereby the PM adhering to the DPF is burned off and the filter is regenerated (Japanese Patent Application Publication No. Hei 08-232639).
Meanwhile, another example of the regeneration operation is self regeneration which uses a DPF in combination with an oxidation catalyst. In the self regeneration, exhaust gas to be introduced into the DPF is constantly maintained at a high temperature, and fuel injected into the exhaust gas by post injection is combusted with the catalyst, whereby PM adhering to the DPF is combusted (Japanese Patent Application Publication No. 2006-241978). By employing this method, the regeneration treatment can be performed continuously, without having to stop the diesel engine.